Problem: Multiply.
Explanation: When a number is next to a variable, it means they are multiplied. So, $({-8}{a^2})({-5}{a^6})$ is the same as $({-8})({a^2})({-5})({a^6})$. Now we can rearrange the factors because multiplication is commutative (a fancy way of saying that the order in which we multiply things doesn't matter). ${(-8)(-5)}{(a^2)(a^6)}$ Then simplify, and we're done! ${40}{a^8}$